1. Field of the Invention
The present invention relates to an optical disk such as the so-called CD and DVD, and more particularly to, an optical disk on which letters and/or patterns are printed.
In this specification, the wording of xe2x80x9cCDxe2x80x9d is used as a general term of a CD-DA (for musical use), a CD-ROM, a CD-R and the like. Furthermore, the wording of xe2x80x9cDVDxe2x80x9d is used as a general term of a DVD-Video, a DVD-ROM, a DVD-R and the like.
2. Description of Related Art
For example, as shown in FIGS. 8 and 9, a conventional compact disk 51 (hereinafter may referred to as xe2x80x9cCDxe2x80x9d) is comprised of a transparent synthetic resin disk substrate 1 having a central chucking aperture 5. The peripheral portion of the chucking aperture constitutes a clamping area 6 having a certain width. On the upper surface of the annular area located outside the clamping area 6, an information-recording layer 2, a reflective layer 3 and a protection layer 4 are laminated in this order.
As shown in a FIG. 10, this compact disk 51 is placed on the disk turntable 83 in the disk player as a drive unit such that the disk chuck 84 is disposed in the chucking central aperture 5. Then, a disk clamper 85 is placed onto the compact disk 51. Thus, the compact disk 51 is clamped by and between the disk clamper 85 and the disk turntable 83. In this clamped state, the compact disk 51 rotates together with the disk turntable 83 and the disk clamper 85 by the motor 88 driving the disk turntable 83. At this time, the upper end of the disk chuck 84 is always located above the upper surface of the compact disk 51.
In this kind of compact disk, a true round disk having a diameter of 12 cm or 8 cm has been provided as a standard size compact disk. On the other hand, recently, as shown in FIG. 11, a rectangular compact disk 61 having a length of from about 85 mm to 89 mm and a width of from about 55 mm to 60 mm has also been proposed. This kind of compact disk 61 is called as a business card-shaped compact disk or a card-shaped compact disk (hereinafter referred to as xe2x80x9ccard-shaped compact diskxe2x80x9d) because of its specific size and configuration.
In this card-shaped compact disk 61, the surface is utilized for label printing. Thus, this card-shaped compact disk 61 can be used as a business card when a person""s name, his/her company name, its telephone/facsimile numbers, etc., are printed thereon. Since this card-shaped compact disk 61 is a kind of compact disk, it is possible to record information in the information-recording layer. Accordingly, a person who obtained this card shaped compact disk 61 can read out the recorded information using a disk-driving device/disk player. Thus, this card-shaped compact disk 61 can function as the same information media as a standard compact disk.
However, in this kind of card-shaped compact disk 61, the chucking central aperture 5 has the some size as that of the 8 cm standard compact disk and the 12 cm standard compact disk, i.e., the diameter of about 1.5 cm, because the card-shaped compact disk 61 is also driven by the same disk-driving device/disk player for standard compact disks. Therefore, in a card-shaped compact disk 61, the rate of occupancy area of the chucking central aperture 5 is larger than that of standard compact disks 51. Accordingly, when this card-shaped compact disk 61 is observed as a business card, the existence of the chucking central aperture 5 looks quite strange and that the arrangement of letters to be printed thereon will be restricted greatly.
Furthermore, besides a business card, the card-shaped compact disk 61 may also be used as, for example, a compact disk for promoting certain music or a compact disk for storing game software. These compact disks may be required to imply the contents of the recorded information by printed patterns, pictures and/or letters thereon. In such a case, the restrictions of design such as illustrations and/or pictures to be printed on the surface of the disk due to the existence of the chucking central aperture 5 is larger than that of letter arrangements to be printed thereon.
Similarly, the aforementioned conventional round compact disk 51 has similar design restriction to be printed thereon. For example, in cases where Mt. Fuji is illustrated on the compact disk 51, the existence of the chucking central aperture 5 spoils the design as shown in FIG. 12.
It is an object of the present invention to provide an optical disk with design freedom of label printing while keeping the chucking ability.
According to a first aspect of the present invention, an optical disk includes a disk substrate made of transparent synthetic resins and an elastic film for label printing. The disk substrate has a chucking central aperture, and the peripheral portion of the chucking central portion constitutes a clamping area. The elastic film is fixed on the upper surface of the disk substrate so as to cover the chucking central aperture. Whereby at least a portion of the film corresponding to the chucking central aperture expands when a disk chuck for chucking the optical disk is inserted into the chucking central aperture and contracts when the disk chuck is pulled out of the chucking central aperture.
According to the present invention, since the chucking central aperture is covered by the elastic film, label printing on the film can be performed without being restricted by the existence of the chucking central aperture.
At the time of chucking the compact disk in a disk-driving device/disk player equipped with a disk clamper, the film covering the chucking central aperture is pushed up by the disk chuck, and a part of the film is chucked assuredly by and between the disk clamper and the disk chuck. Therefore, the compact disk can be chucked more firmly, which prevents rotational fluctuation of the compact disk.
In a disk-driving device in the so-called notebook computer which is not equipped with a disk clamper, the film covering the chucking central aperture is pushed up by a disk chuck when the disk chuck is inserted into the chucking central aperture. Therefore, engaging hooks of the disk chuck can be assuredly engaged with the inner edge of the clamping area of the compact disk, resulting in no chucking trouble.
When the compact disk is taken out of the disk-driving device/disk player after the releasing of the chucking, the portion of the film pushed up by the disk chuck returns to the original flat state because of its elasticity. Since the deformed patterns and/or letters due to the deformation of the film at the time of chucking will be restored in accordance with the releasing of the chucking, the design of the patterns and/or letters printed on the film will not be spoiled.
It is preferable that the film is made of vinyl chloride resins, polyolefin resins such as polypropylene or polyethylene, polyester resins such as polyethylene terephthalate, polyurethane resins, or latex, which is rich in elasticity.
In order to keep the deforming area of the film as large as possible and effectively prevent the film from being damaged at the time of chucking, it is preferable that the portion of the film corresponding to the clamping area of the disk substrate is not fixed to the disk substrate while the remaining portion is fixed.
In general, adhesive agent is employed to fix the film on the disk substrate. Alternatively, any other fixing method such as welding may be employed.
Furthermore, it is preferable that the film is a non-transparent laminated film comprising a film body and a metal deposition layer such as an aluminum deposition layer deposited on the rear surface of the film body because of the following reasons. In cases where the film is optically permeable, the portion of the disk where the reflective layer is provided and the remaining portion will be distinctively recognized as a background of the optical disk, resulting in a poor looking disk. To the contrary, in cases where the film includes a metal deposition layer, there will be no such drawback, resulting in a good-looking disk.
It is preferable that printings such as patterns and/or letters are formed on the rear surface of the film so as not to blur or fade away due to friction or the like.
It is preferable that the thickness of the film falls within the range of from about 0.01 to 0.03 mm because of the following reasons. When the thickness of the film exceeds about 0.01 mm, the amount (i.e., thickness) of the film to be disposed between a disk chuck and a disk clamper increases, resulting in inadequate pressing force onto the clamping area by the disk clamper, which may cause rotational fluctuation of the disk. On the other hand, when the thickness of the film is less than about 0.03 mm, the strength of the film becomes inadequate, which may cause breakage of the film.
According to the second aspect of the present invention, an optical disk includes a disk substrate made of transparent synthetic resins and a non-elastic film for label printing. The disk substrate has a chucking central aperture, and a peripheral portion of the chucking central portion constitutes a clamping area. The non-elastic film is fixed on an upper surface of the disk substrate so as to cover the chucking central aperture. The non-elastic film is provided with cuts at a portion corresponding to the chucking central aperture, whereby the cut portion opens when a disk chuck for chucking the optical disk is inserted into the chucking central aperture and closes when the disk chuck is pulled out of the chucking central aperture.
It is preferable that the non-elastic film is a paper having crossing cuts such as an X-shaped cuts.
Other objects and the features will be apparent from the following detailed description of the present invention with reference to the attached drawings.